Our R25T Training Program in Cancer-related Population Sciences, a joint effort of Columbia's Mailman School of Public Health and Herbert Irving Comprehensive Cancer Center (HICCC), is now completing its 14th year and will not be eligible for renewal; thus, we submit this competitive renewal for an equivalent T32 grant. Funded continuously since 1985 by NCI T32 and R25T grants, we have provided multidisciplinary training to 45 predoctoral and 70 postdoctoral trainees. Most of them have developed successful academic careers, and many are now leaders in cancer epidemiology, biostatistics, carcinogenesis, survivorship and health outcomes research nationally. Since 2002, our R25T program has had 30 trainees. In its current cycle (2012-2017), it hosts 4 postdoctoral research fellows annually across 3 public health disciplines, supported by 19 R01-funded primary mentors and 24 secondary mentors. The average NIH grant portfolio of our primary mentors is $1.9 million/year. Past R25 trainees have published a mean of 8.75 papers with a mean of 3.5 first authored, and 20 out of 22 trainees from the last 10 years remain in research. We also have an outstanding applicant pool; 73% of applicants are training grant eligible; 18% selectivity; and 20% of trainees from underrepresented racial/ethnic groups. This competitive renewal reports on new leadership at Mailman, the participating departments, and the NCI-funded HICCC, all of whom are deeply committed to ensuring the longstanding success of our Training Program and our fellows. Mailman provides salary support for the two PIs and part- time administrative assistant as well as space and support for the trainees. Our location in northern Manhattan, including Washington Heights and Harlem with their large underserved minority populations, and our close relationships with the New York City Department of Health, made us early leaders in disparities research, and our trainees benefit tremendously from those resources. In addition, our large portfolio of international collaborative projects, together with our catchment area studies, provides our fellows with a global perspective on cancer and the changing dynamics of the cancer epidemic, which is best understood through contrasts in study populations and exposures. Our leadership in health outcomes research and survivorship, as well as the emerging field of cancer care delivery research (CCDR) has gained us a large number of fellows in medical, pediatric, surgical and gynecologic oncology as trainees. We offer training modules in study design, clinical, behavioral, laboratory, health services, and data analysis. Our program also includes weekly journal clubs, biweekly seminars, a formal evaluation protocol, and mock study sections. We regularly interact with our External Advisory Board and invite them to visit annually to meet our fellows and hear about their research. A collaboration of epidemiology, biostatistics, and environmental health sciences, including clinical and laboratory training opportunities, our program offers a superb multidisciplinary, multidimensional milieu in which trainees can develop their research skills and find their own niches.